This invention is in the field of billfold bill files and having multiple panels, each one with an index tab designating a different currency bill figure.
The field is illustrated by my patent U.S. Pat. No. 4,049,035 which issued Sept. 20, 1977, titled, CURRENCY BILL BILLFOLD FILE, inventor: Donald J. Finn.
In this patent application, the object was to make the panels so thin that they would not interfere with the folding of the billfold in such a manner as to make the billfold bunch up. The process of solving this problem involves a very expensive solution with very thin panels of very light thermoplastic material, such as flexible polypropylene of approximately 0.010 inch thickness.
A problem experienced is that material of such a small thickness tends to wrinkle so that the billfold file becomes unsightly and eventually not sufficiently functional.
Another patent application in my name titled, BILLFOLD BILL FILE, Ser. No. 746,196, was filed Nov. 30, 1976, and is now U.S. Pat. No. 4,134,437. In this case, the panels are of a semi-soft polypropylene of a thickness of approximately 0.010 or 0.015 inch thickness, in general, with certain areas adjacent folds where the billfold itself would fold being of approximately 0.005 thickness for ease of folding. However, it was my experience that although folding might be easier and economy was simpler, yet the thin panels tend to wrinkle and crumple.
I also applied for a patent, Ser. No. 795,647, filed May 10, 1977, titled: BILLFOLD FILE, on a construction which the intention was to have panels of very thin thermoplastic material of a thickness of approximately six and one-half mills to provide some thickness for the support of the tabs, but in general, a great thinness for ease of folding. Again the problem was crumpling and wrinkling of the material of the panels.
In these various applications, considerable attention was given to the way the panels are secured together and how the panels are secured to the billfold for minimizing the wrinkling of the panels resultant from the folding of the billfold. But, one problem was common to all of these billfold files, and that was that the panels cold vertically wrinkle by crumpling down toward the bottom of the billfold, simply because of the thinness of the panels. There was a dilemma. There was no way out. If the panels were made thicker, then the billfold got too bulky. If they were thin, they would crumple down toward the bottom of the billfold after substantial periods of use.
It is the object of this invention to eliminate one feature that was common to all of these previous inventions of mine, namely, to eliminate the having of the billfold panels extending substantially from one end of the billfold to the other. This made use of my later discovery that it was not necessary to have the panels going the length of the billfold. It was, instead, possible to have the panels be in only one section of the billfold and disposed between, either the two fold areas of a double-fold billfold, or between an end and the fold area of a single-fold billfold. This discovery reduced the volume of the material in a billfold by one-half, in terms of area, leaving more possibility for the panels to be thick so that they could be more stiff and resistant to crumpling down so that they would not crumple down toward the bottom of the billfold as the file was used.
Another advantage of my minimum panel area billfold file is the savings in material cost.